• Asian-Australasian Journal of Animal Sciences
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• v.8 no.6
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• pp.533-555
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• 1995

Direct-fed microbials (DFM) have been used to enhance milk production in lactating cattle and to increase feed efficiency and body weight gain in growing ruminants. Primary microorganisms that have been used as DFM for ruminants are fungal cultures including Aspergillus oryzae and Saccharomyces cerevisiae and lactic acid bacteria such as Lactobacillus or Streptococcus. Attempts have been made to determine the basic mechanisms describing beneficial effects of DFM supplements. Various modes of action for DFM have been suggested including : stimulation of ruminal microbial growth, stabilization of ruminal pH, changes in ruminal microbial fermentation pattern, increases in digestibility of nutrients ingested, greater nutrient flow to the small intestine, greater nutrient retention and alleviation of stress, however, these responses have not been observed consistently. Variations in microbial supplements, dosage level, production level and age of the animal, diet and environmental condition or various combinations of the above may partially explain the inconsistencies in response. This review summarizes production responses that have been observed under various conditions with supplemental DFM and also corresponding modification of ruminal fermentation and other changes in the gastrointestinal tract of ruminant animals.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.1
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• pp.131-136
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• 2006

During lactic acid bacteria (LAB) transit through the gastrointestinal tract, ingested microorganisms were exposed to successive stress factors, including low pH in the human stomach and in bile acid. These stress factors can be used as criteria for the selection of a viable probiotic strain. Four such strains (Lactobacillus helveticus SGU 0011, Lactobacillus pentosus SGU 0010, Streptococcus thermophilus SGU 0021 and Lactobacillus casei SGU 0020) were isolated from raw milk. When the identified LAB were exposed to synthetic gastric juice, whereas L. casei SGU 0020 and S. thermophilus SGU 0021 exhibited a 0% survival rate, L. helveticus SGU 0011 and L. pentosus SGU 0010 exhibited 60% and 95% survival rates. L. casei SGU 0020 and S. thermophilus SGU 0021 could not be examined with regard to their tolerances to artificial bile juice, as they uniformly died upon exposure. However, L. helveticus SGU 0011 and L. pentosus SGU 0010 individually survived at rates of 39% and 93%. Also, all four of these strains were confirmed to be tolerant of ten different antibiotics.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.31 no.3
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• pp.131-145
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• 2020

The microbiota-gut-brain axis, which refers to the bidirectional communication pathway between gut bacteria and the central nervous system, has a profound effect on important brain processes, from the synthesis of neurotransmitters to the modulation of complex behaviors such as sociability and anxiety. Previous studies have revealed that the gut microbiota is potentially related to not only gastrointestinal disturbances, but also social impairment and repetitive behavior-core symptoms of autism spectrum disorder (ASD). Although studies have been conducted to characterize the microbial composition in patients with ASD, the results are heterogeneous. Nevertheless, it is clear that there is a difference in the composition of the gut microbiota between ASD and typically developed individuals, and animal studies have repeatedly suggested that the gut microbiota plays an important role in ASD pathophysiology. This possibility is supported by abnormalities in metabolites produced by the gut microbiota and the association between altered immune responses and the gut microbiota observed in ASD patients. Based on these findings, various attempts have been made to use the microbiota in ASD treatment. The results reported to date suggest that microbiota-based therapies may be effective for ASD, but largescale, well-designed studies are needed to confirm this.

• Journal of Microbiology and Biotechnology
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• v.26 no.8
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• pp.1490-1503
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• 2016

Colorectal cancer (CRC) is the third most common cancer in the world. Although 5-fluorouracil (5-FU) is the representative chemotherapy drug for colorectal cancer, it has therapeutic limits due to its chemoresistant characteristics. Colorectal cancer cells can develop into cancer stem cells (CSCs) with self-renewal potential, thereby causing malignant tumors. The human gastrointestinal tract contains a complex gut microbiota that is essential for the host's homeostasis. Recently, many studies have reported correlations between gut flora and the onset, progression, and treatment of CRC. The present study confirms that the most representative symbiotic bacteria in humans, Lactobacillus plantarum (LP) supernatant (SN), selectively inhibit the characteristics of 5-FU-resistant colorectal cancer cells (HT-29 and HCT-116). LP SN inhibited the expression of the specific markers CD44, 133, 166, and ALDH1 of CSCs. The combination therapy of LP SN and 5-FU inhibited the survival of CRCs and led to cell death by inducing caspase-3 activity. The combination therapy of LP SN and 5-FU induced an anticancer mechanism by inactivating the Wnt/β-catenin signaling of chemoresistant CRC cells, and reducing the formation and size of colonospheres. In conclusion, our results show that LP SN can enhance the therapeutic effect of 5-FU for colon cancer, and reduce colorectal cancer stem-like cells by reversing the development of resistance to anticancer drugs. This implies that probiotic substances may be useful therapeutic alternatives as biotherapeutics for chemoresistant CRC.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.24 no.3
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• pp.245-255
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• 2021

Necrotizing enterocolitis (NEC) is a disease with high morbidity and mortality that occurs mainly in premature born infants. The pathophysiologic mechanisms indicate that gastrointestinal dysbiosis is a major risk factor. We searched for relevant articles published in PubMed and Google Scholar in the English language up to October 2020. Articles were extracted using subject headings and keywords of interest to the topic. Interesting references in included articles were also considered. Network meta-analysis suggests the preventive efficacy of Bifidobacterium and Lactobacillus spp., but even more for mixtures of Bifidobacterium, Streptococcus, and Bifidobacterium, and Streptococcus spp. However, studies comparing face-to-face different strains are lacking. Moreover, differences in inclusion criteria, dosage strains, and primary outcomes in most trials are major obstacles to providing evidence-based conclusions. Although adverse effects have not been reported in clinical trials, case series of adverse outcomes, mainly septicemia, have been published. Consequently, systematic administration of probiotic bacteria to prevent NEC is still debated in literature. The risk-benefit ratio depends on the incidence of NEC in a neonatal intensive care unit, and evidence has shown that preventive measures excluding probiotic administration can result in a decrease in NEC.

• Journal of Dairy Science and Biotechnology
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• v.39 no.2
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• pp.51-62
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• 2021

Escherichia coli are the predominant facultative bacteria found in the gastrointestinal tract of animals and humans. Some strains of E. coli that acquire virulence factors and cause foodborne and waterborne diseases in humans are called pathogenic E. coli and can be divided into five pathotypes according to the virulence mechanism: EAEC, EHEC, EIEC, EPEC, and ETEC. Although selective media have been developed to detect E. coli, distinguishing pathogenic strains from non-pathogenic ones is difficult because of their similar biochemical properties. Therefore, it is very important to find a new and effective diagnostic method to identify pathogenic E. coli. With recent advances in molecular biology and whole genome sequencing, the use of polymerase chain reaction (PCR) is increasing rapidly. In this review paper, we provide an overview of pathogenic E. coli and present a review on PCR detection methods that can be used to diagnose pathogenic E. coli. In addition, the possibility of real-time PCR incorporating IAC is introduced. Consequently, this review paper will contribute to solving the current challenges related to the detection of pathogenic E. coli.

• Biomolecules & Therapeutics
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• v.32 no.4
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• pp.403-423
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• 2024

The human gastrointestinal (GI) tract houses a diverse microbial community, known as the gut microbiome comprising bacteria, viruses, fungi, and protozoa. The gut microbiome plays a crucial role in maintaining the body's equilibrium and has recently been discovered to influence the functioning of the central nervous system (CNS). The communication between the nervous system and the GI tract occurs through a two-way network called the gut-brain axis. The nervous system and the GI tract can modulate each other through activated neuronal cells, the immune system, and metabolites produced by the gut microbiome. Extensive research both in preclinical and clinical realms, has highlighted the complex relationship between the gut and diseases associated with the CNS, such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. This review aims to delineate receptor and target enzymes linked with gut microbiota metabolites and explore their specific roles within the brain, particularly their impact on CNS-related diseases.

• Korean journal of food and cookery science
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• v.15 no.6
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• pp.555-564
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• 1999

The objective of this study was to investigate the preference of root vegetables and the inhibitory effect of the vegetables on harmful enzymes of intestinal bacteria. Two hundred fifty respondents in Seoul area surveyed to obtain information from Sep. 30 to Oct. 30, 1998. Respondents preferred Inpuomoea batatas (sweet potato, 4.05), Solanum tuberosum(potato, 3.97), Allium cepa(onion, 3.68), Codonopsis lanceolata(3.64) and Raponus sativus(redish, 3.60). The growth of B. breve K-110 was effectively increased by adding 0.5% extract of Solanum tuberosum(139%), Codonopsis lamceolate(145%), Dioscorea japonica(164%), Colocisia antiquorum(144%) extract to the medium. B. breve K-100 for beneficial bacteria, and E. coli HGU-3 or Bacteroides JY-6 for harmful bacteria were used to determine the inhibitory effect of root vegetables on harmful intestinal enzymes after co-culturing harmful and beneficial bacteria. The extract of Solanum tuberosum, Codonopsis lanceolata, Dioscorea japonica (yam) and Colocisia antiquorum (taroes) showed inhibitory effect on ${\beta}$-glucuronidase and tryptophanase of intestinal bacteria. The macromolecules were isolated from Solanum tuberosum, Codonopsis lanceolata, Dioscorea japonica and Colocisia antiquorum by Sephadex G-100 column chromatography. By adding these isolated marcromolecules to the medium, the growth of B. breve K-100 were also increased and high inhibitory effects on the ${\beta}$-glucuronidase and tryptophanase were measured. These results suggested that the harmful enzymes of intestinal bacteria were inhibited by consuming Solanum tuberosum, Codonopsis lanceolata, Dioscorea japonica and Colocisia antiquorum. Therefore, they could prevent gastrointestinal diseases.

• Journal of Life Science
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• v.22 no.10
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• pp.1307-1315
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• 2012

We evaluated the effect of dietary supplements with benzoic acid on intestinal beneficial bacteria concentration and immune response of weaning pigs. Supplementation with benzoic acid at 0.5% or control diet for 35 days resulted in a higher Lactobacillus casei concentration in the cecum. Supplementation with benzoic acid at 0.5% increased concentration of L. plantarum in the cecum. Pigs with the control diet and 0.5% benzoic acid had significantly increased concentration of B. subtillis in the cecum compared to the antibiotic group, while the concentration of B. subtillis in the rectum increased in pigs given 0.3 and 0.5% benzoic acid (p<0.05). Compared with the control group, the level of interleukin-$1{\beta}$ mRNA showed a significant decrease in the proximal small intestine in pigs fed diets supplemented with benzoic acid at 0.5% or antibiotic. Feeding 0.5% benzoic acid resulted in a marked reduction in the expression of IL-6 mRNA in the middle small intestine (p<0.05). Supplementation with benzoic acid at 0.5% or antibiotic resulted in a lower level of tumor necrosis factor-mRNA in the middle intestine. Up to 0.5% benzoic acid may be included in weaning diets for improvement of intestinal beneficial bacteria, thus modulating genes of pro-inflammatory cytokines in the gastrointestinal tract.

• Journal of Food Hygiene and Safety
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• v.17 no.2
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• pp.71-78
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• 2002

With the incidence of antibiotic resistant bacteria there is increasing interest in natural products such as herb extract and probiotics to control antibiotic resistant bacteria. This study was focused on the determination of antimicrobial activity of Opuntia ficus-indica var. saboten against Salmonella enetrica serovar Enteritidis (S. enterifidis), S. enterica serovar Typhimurium (S. Typhimurium) DT 104 and Escherichia coli 0157:H7. Though bactericidal effect of 0. ficus-indica var. saboten was not observed, it had significant inhibitory activity against Salmonella spp. and E. coli O157:H7 on the Moulter Hinton agar containing its solution dissolved in deionized water. To investigate the antimicrobial activity in vivo, mice were challenged with 5. Typhimurium DT104 (3.7$\times$108 cfu/mouse) after pre-feeding 0. ficus-indica var. saboten solution. The fecal shedding of S. Typhimurium DT104 was more dramatically decreased and not detectable in feces and intestines 3 days after challenge in mice fed with 0. ficus-indica var. saboten. Antibody responses of the intestinal IgA were also significantly increased in mice fed with 0. ficus-indica var. saboten. These findings suggest that Opuntia ficus-indica var. saboten decreased the shedding of S. Typhimurium DT104 in vitro and also in the gastrointestinal tract in mice. In addition, administration of the product might enhance the mucosal immune response against S. Typhimurium DT 104. In conclusion, Opuntia ficus-indica var. saboten might be useful to control antibiotic resistant bacteria in vivo and in vitro.